$baseScreenWidth: 640px !default;   /* Design draft screen width */
$baseScreenHeight: 1200px !default; /* Design draft screen height */
$baseFontSize: 36px !default;       /* Rem base font size */

@function strip-unit($num) {
  @return $num / ($num * 0 + 1);
}

@function rem($pixel) {
  @return strip-unit($pixel) / strip-unit($baseFontSize) * 1rem;
}

@function pixel($rem) {
  @return strip-unit($rem) * strip-unit($baseFontSize) * 1px;
}

@function percentToWidth($pixel) {
  @return strip-unit($pixel) / strip-unit($baseScreenWidth) * 100%;
}

@function percentToHeight($pixel) {
  @return strip-unit($pixel) / strip-unit($baseScreenHeight) * 100%;
}
@mixin boxShadow($x:0,$y:0,$r:0){
  -moz-box-shadow:$x $y $r;
  -webkit-box-shadow:$x $y $r;
  box-shadow:$x $y $r;
}